Magnesium is the lightest structural metal. In engineering applications it is alloyed with one or more elements, for example, aluminum, manganese, rare earth metals, lithium, zinc, and silver. Magnesium usually constitutes eighty-five percent by weight or more of these alloys.
The cost of magnesium has decreased dramatically in recent years and magnesium and its alloys have become attractive structural materials for a wide range of applications due in part to desirable physical properties such as light weight, high specific strength and stiffness, machinability, and the ability to be easily recycled. However, the use of magnesium in wrought products like sheets and extrusions has been limited due to the poor workability of magnesium castings and the lower formability and ductility of magnesium in the primary fabricated stage. At room temperature, pure magnesium is generally characterized by limited ductility as a result of its hexagonal close-packed crystal structure and resulting limited number of active slip systems. This inherent limitation often discourages widespread use of magnesium in wrought products made from sheets and extrusions because it is difficult and expensive to process the poorly workable metal into useable finished shapes.
It has been shown that the ductility of Mg-0.2 wt % Ce alloy extrusions is higher than that of magnesium and other known magnesium alloys. However, the yield and tensile strengths of the Mg-0.2 wt % Ce alloy remain low. The addition of aluminum to the Mg-0.2 wt % Ce alloy improves its strength, but significantly decreases its ductility.
Thus, there is a general need to provide magnesium alloys in a primary fabrication stage having improved ductility and strength for fabrication into wrought magnesium metal products.